Trump also delivered a scolding to South Korea, a longtime U.S. ally, stating that "appeasement with North Korea will not work".

Trump's response to North Korea's nuclear test included an admonishment of South Korea

Washington: President Donald Trump sharply condemned North Korea's overnight nuclear test, saying Sunday morning that the action - which defied Trump's blunt warnings - were "very hostile and dangerous to the United States."

Trump's response to North Korea's announcement that it had detonated a hydrogen bomb that could be attached to a missile capable of reaching the mainland United States included an admonishment of South Korea for its handling of the nuclear crisis.

In a pair of tweets issued Sunday morning, Trump wrote: "North Korea has conducted a major Nuclear Test. Their words and actions continue to be very hostile and dangerous to the United States. . .North Korea is a rogue nation which has become a great threat and embarrassment to China, which is trying to help but with little success."

Trump also delivered a scolding to South Korea, a longtime U.S. ally, stating that "appeasement with North Korea will not work" and suggesting that more severe steps must be taken to influence Kim Jong Un's government.

In a third Sunday morning tweet, the president wrote, "South Korea is finding, as I have told them, that their talk of appeasement with North Korea will not work, they only understand one thing!"

This comes amid escalating economic tensions with South Korea, a democratic nation and a longtime economic and diplomatic partner with the United States. Trump is considering withdrawing the United States from a free-trade agreement with South Korea.

The move would be in keeping with Trump's campaign promise to end what he considers unfair trade competition from foreign countries, but the president's advisers have cautioned would strain ties with South Korea amid the mounting North Korean nuclear crisis.

Trump weighed in Sunday morning from the White House. His comments came just a few hours after he spoke with Japanese Prime Minister Shinzo Abe, a key ally in the region.

In a Saturday evening phone call - which Trump made from aboard Air Force One as he returned home to Washington from his visit to storm-battered Texas and Louisiana - the two leaders discussed "ongoing efforts to maximize pressure on North Korea," according to the White House.

"The two leaders reaffirmed the importance of close cooperation between the United States, Japan and South Korea in the face of the growing threat from North Korea," read a statement from the White House.

Trump also spoke recently with South Korean President Moon Jae-in. In a call on Friday, the two leaders talked about "our coordinated response to North Korea's continued destabilizing and escalatory behavior," according to the White House.

"President Trump and President Moon pledged to continue to apply strong diplomatic and economic pressure on North Korea and to make all necessary preparations to deter and defend against the growing threat posed by North Korea," read a White House statement. "The two leaders agreed to strengthen our alliance through defense cooperation and to strengthen South Korea's defense capabilities. President Trump provided his conceptual approval of planned purchases by South Korea of billions of dollars in American military equipment."

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